SENIOR Liberals are stepping up efforts to turn corruption allegations against the Reserve Bank into a political headache for federal Labor.

The shadow treasurer, Joe Hockey, has made his first intervention into allegations of bribes paid to win foreign note-printing contracts, backing moves to return the Reserve Bank governor, Glenn Stevens, to front a parliamentary hearing into the scandal.

The Prime Minister, Julia Gillard, and the Treasurer, Wayne Swan, have given firm support to Mr Stevens, despite inconsistencies emerging in accounts of when he first became aware of the allegations.

But Mr Hockey told opposition MPs yesterday the problems at the banknote firm Securency amounted to a major issue because it involved allegations of corruption at the Reserve Bank. Authorities last year charged the Reserve companies Securency and Note Printing Australia with bribing foreign officials to win lucrative contracts using plastic note-printing technology pioneered in Australia.

The opposition has cautiously but steadily expressed concern in recent months over growing claims of a cover-up and Labor's refusals to set up a full inquiry into the conduct of bank officials.

''It is not only what has happened in the past - it is how the matter has been handled by the government now,'' the deputy leader of the Liberals, Julie Bishop, said.